The invention relates to a stiffening component for monitoring the functionality of a structural adhesive layer to be fabricated between the latter and another component.
In addition, the invention relates to a method for manufacturing a structural adhesive layer between such a stiffening component and another component, which can be checked in particular with respect to its functionality. Finally, the invention relates to a combing tool, in particular for implementing the method.
Increasing use is being made of CFRP components in modern aircraft construction. The CFRP components fabricated by suppliers are adhesively bonded in the aircraft structures to be manufactured within a time-critical production phase. Sensors for nondestructively monitoring the functionality of the adhesive bonds established in this way (so-called “NDT”, nondestructive testing) during the production process and during ongoing airline operations are currently not integrated into the assemblies, among other reasons for cost considerations. Such sensors, for example which can be so-called “SHM sensors” (structural health monitoring sensors), are advantageous, however, since the currently available numerical calculation algorithms for determining the load-bearing capacity of CFRP components and their adhesive bonds do not have the level of accuracy necessary to completely exhaust the weight saving potential of the CFRP assemblies in comparison to the classic aluminum structure. In the case of CFRP components, this means that an additional level of mechanical safety must be provided by increasing the material thickness of the component and/or reinforcing the adhesive bonds in order to offset the inevitable calculation uncertainties. This generally results in an undesirable increase in weight of the CFRP component.
In addition, the process of manufacturing large-scale, complex CFRP components is extremely time-critical, since the curing processes for the utilized duroplastics, such as the widely used epoxy resins, have narrow tolerances in terms of time. As a consequence, prior art does not yet make it possible to integrate a complex array of sensors for structural health monitoring into the CFRP assemblies during the manufacturing process.
WO 01/84102 A1 discloses a vacuum system and a method for the detection of cracks and acquisition of crack propagation in components and structures. However, the previously known system is not provided for continuously monitoring a structural adhesive layer between two adhesively joined components. In addition, the vacuum system cannot be integrated into a high number of structural components without any loss of time.